The STOP Project will be carried out as a randomized clinical trial to evaluate different approaches to smoking cessation within physician practice settings. This project is a collaborative effort between the NICHD and the American College of Obstetricians and Gynecologists. The unit of randomization in STOP will be a practicing physician's population of pregnant women who smoke or have recently stopped smoking. Physicians will be solicited to volunteer to take part in this randomized study. There will be two major phases to the STOP Project - a pretest-pilot and a formal trial. The objective of the pilot study is to develop the protocol for the STOP study, develop all study materials (pamphlets, study forms, manual of operations, etc.), recruit private physicians who will assist us in finalizing the study protocol and materials, assist in the development of all quality control procedures, and train the contractor selected to run the formal trial in all aspects of the study. All study materials (forms, urine testing, pamphlets etc.) will be modified to be easily incorporated into the daily routines of private physicians' offices. The desired result of the pilot will be to have all necessary forms, materials, etc. complete and ready for use in the formal STOP study. At this time all of our educational materials have been completed and approved by the physicians and staff assisting us in the pretest-pilot phase. On July 27, 1990 we will be holding the scientific peer review for the STOP proposals. It is expected that a contractor will be identified and the contract will be let in October 1990.